EF Core中的IsNumeric [英] IsNumeric in EF Core

问题描述

在EF Core中或通过使用linq或Dynamic Sql或类似方法是否存在IsNumeric的等效项？

我试图从nvarchar列中仅获取具有数字值的行。

解决方案

您可以使用

EF核心的实体类：Sandbox.cs

 公共类Sandbox 
 {
 public int SandboxId {get;组; } 
公共字符串StringOrNumber {get;组; } 
} 
  

在您的上下文中创建DbSet：

  public DbSet< Sandbox>沙盒{get;组; } 
  

标记为无键：

  modelBuilder.Entity&Sandbox>（）。HasNoKey（）; 
  

测试：

 公共异步任务< IList< Sandbox>> GetNumberList（）
 {
 // 1 =数字，0 =字符串
 var isNumeric = new SqlParameter（ isNumeric，1）; 
 
 var listOfNumbers =等待_context.Sandboxes 
 .FromSqlRaw（ SELECT SandboxId，StringOrNumber FROM dbo.Sandbox WHERE ISNUMERIC（StringOrNumber）= @isNumeric，isNumeric）
 .ToListAsync（ ）; 
 
返回listOfNumbers; 
} 
  

FromSqlRaw的替代方法是

Is there an equivalent of IsNumeric in EF Core or by using linq or Dynamic Sql or similar?

I am trying to get only the rows with numeric values from a nvarchar column.

解决方案

You could use Raw SQL Queries

Security Note: Always use parameterization for raw SQL queries

Given this dataset/result:

The entity class for EF Core: Sandbox.cs

    public class Sandbox
    {
        public int SandboxId { get; set; }
        public string StringOrNumber { get; set; }
    }

Create a DbSet in your context:

    public DbSet<Sandbox> Sandboxes { get; set; }

Mark as no key:

    modelBuilder.Entity<Sandbox>().HasNoKey();

Test:

    public async Task<IList<Sandbox>> GetNumberList()
    {
        // 1 = number, 0 = string
        var isNumeric = new SqlParameter("isNumeric", 1);

        var listOfNumbers = await _context.Sandboxes
        .FromSqlRaw("SELECT SandboxId, StringOrNumber FROM dbo.Sandbox WHERE ISNUMERIC(StringOrNumber) = @isNumeric", isNumeric)
        .ToListAsync();

        return listOfNumbers;
    }

An alternative to FromSqlRaw is FromSqlInterpolated.

    var listOfNumbers = await _context.Sandboxes
    .FromSqlInterpolated($"SELECT SandboxId, StringOrNumber FROM dbo.Sandbox WHERE ISNUMERIC(StringOrNumber) = {isNumeric}")
    .ToListAsync();

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